A conventional modulation and demodulation manner is as follows: After an antenna acquires a radio frequency (RF) signal, the radio frequency signal is first converted into an intermediate frequency signal, and then the intermediate frequency signal is converted into a baseband signal, where the baseband signal may be an in-phase/quadrature (I/Q) signal. A zero intermediate frequency technology is a modulation and demodulation method for directly converting an RF signal into a baseband signal without using an intermediate frequency signal.
In recent years, as devices develop, the zero intermediate frequency technology is widely applied, and gradually becomes mature. A working principle of a transceiver in a zero intermediate frequency architecture is as follows. A baseband signal is input to a quadrature modulator through I and Q channels, and the quadrature modulator performs quadrature modulation on an I signal and a Q signal. Additionally, the transceiver transmits signals output by the quadrature modulator.
Because an actual quadrature modulator generally cannot implement complete quadrature for two signals, a quadrature modulation error is caused. Such an undesired problem of the quadrature modulator may cause carrier leakage and imbalance between the I signal and the Q signal. The imbalance between the I signal and the Q signal may cause an image component, and the image component may cause a decrease in signal quality. Therefore, a transceiver that uses the zero intermediate frequency technology needs to perform correction processing.
A current correction method is as follows: adding a corresponding feedback module or coupling module between a transmit end and a receive end of a transceiver; calculating a corresponding compensation coefficient by comparing a feedback signal and a baseband signal; and performing corresponding compensation. Adding of the feedback module or coupling module increases hardware costs of the transceiver, and increases complexity of hardware design.